Roof vents which are presently made for sloping roofs are made of a tubular pipe cut at an angle and welded to a flat ring, the angle of the pipe corresponding to the angle of the sloping roof. Such method of constructing roof vents usually leads to vents which are leaking around the soldered parts and accordingly, does not provide satisfactory results. Furthermore, this method of producing tilted vents requires many operations which raises the cost of the final product.
In U.S. Pat. No. 4,214,513, issued on July 29, 1980, Ballard et al. describes a one-piece roof vent device and methods of constructing and utilizing the same. Although, this vent device is made out of one piece, its construction is symetrical relative to the vertical axis of the vent. This vent device is also intended for flat roofs and the method can not be concieved to be built on an annular base portion tilted relative to the longitudinal axis of the vent device.